The present invention relates to a sealing assembly for two relatively rotating members, in particular the two rings of a rolling-contact bearing, and of the type incorporating a magnetic ring cooperating with a detecting device outside the assembly to detect the relative rotation speed of the two members.
Numerous sealing assemblies of the above type are known. In particular, the magnetic ring is known to be fitted directly, with a small amount of interference, to the rotary ring of the bearing or to a rigid metal shield fitted to the ring. Such a solution, however, has the drawbacks of exposing the magnetic ring, especially if made of relatively fragile material, to damage both during assembly and in use; transmitting to the magnetic ring vibration which may impair operation of the detecting device; and failing to withstand other than a limited amount of thermal expansion (due to the different expansion coefficients of the magnet and bearing materials) and mechanical stress (shock).
It is an object of the present invention to provide a sealing assembly incorporating a magnetic ring and designed to eliminate the aforementioned drawbacks. More specifically, it is an object of the invention to provide a sealing assembly which is effective, is cheap and easy to produce, is extremely compact, and in which operation of the indicating member remains fully reliable.
According to the present invention, there is provided a sealing assembly for two relatively rotating mechanical members, in particular the two rings of a rolling-contact bearing, and of the type comprising a first shield for integral connection to a first of said mechanical members; a sealing ring carried by said first shield and cooperating in fluidtight manner with a second shield connectable to a second of said mechanical members; and a magnetic ring carried by said first shield; said first shield having a radial flange and a covering of elastomeric material extending at least partly on one face of said flange; and the sealing assembly being characterized in that said magnetic ring projects axially from said face of the flange; said covering comprising a base portion interposed axially between said flange and said magnetic ring, and deformable locating and supporting means for locating and supporting said magnetic ring; and an annular surface of said magnetic ring being bonded to said base portion of the covering.
As such, the magnetic ring is not connected directly to a rigid member, and is therefore unaffected by vibration or stress, which are damped by the covering of elastomeric material. At the same time, the magnetic ring is favourably located to ensure correct operation of the detecting device, and the assembly as a whole is extremely compact, particularly axially; the sealing assembly according to the invention is quick and easy to assemble; and different types of magnetic rings, in particular made of magnetic mixture or plastic ferrite, can be used.